Months after the presumptive Republican presidential nominee first caught flak for being noncommittal about disavowing the support of David Duke and the Ku Klux Klan, Trump is again forced to separate himself from his controversial constituency.

California's secretary of state on Monday published a list of delegates provided by the Trump campaign. Among the 169 names listed was William Johnson, a noted white nationalist and leader of the American Freedom Party.

An earlier Trump campaign statement cited by an NBC News reporter blamed a "database error" for Johnson's inclusion. In a follow-up statement, Trump's campaign removed the database error reference, saying that Johnson "had been rejected and removed from the campaign's list in February 2016."

A spokesperson for the California Secretary of State's office said "the Trump campaign did not reach out to our office about removing William Johnson's name as a delegate until today (Tuesday May 10), which is past the statutory deadline."

Johnson's American Freedom Party, which describes itself as one that "represents the interests and issues of European-Americans," also describes the Democratic and Republican parties as "more alike than they are different."

Donald Trump is running on the Republican ticket.

The frontrunner's candidacy has, at times, been overshadowed by his broad support among white nationalists. Johnson's party has spent thousands of dollars on pro-Trump robocalls, Reuters reported in January. Those calls made pronouncements like "We don't need Muslims. We need smart, well-educated white people who will assimilate to our culture."

Trump has proposed temporary bans on Muslims entering the US.

Matt Mills McKnight/Getty Images

Trump previously disavowed white-nationalist support in television interviews and, in one case, blamed "a very bad earpiece" for not doing it sooner.

Here's the full statement from the Trump campaign:

Yesterday the Trump Campaign submitted its list of California delegates to be certified by the Secretary of State of California. Upon careful review of computer records, the inclusion of a potential delegate that had previously been rejected and removed from the campaign's list in February 2016, was discovered. This was immediately corrected and a final list, which does not include this individual, was submitted for certification.